Difference between revisions of "Overview"

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[[Main Page]] > [[Documentation]] > [[Technical Architecture]] > Overview
  
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==Open source OAIS==
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Archivematica provides an integrated suite of free and open-source tools that allows users to process digital objects from [[Micro-services#Archivematica_Micro-services|ingest to archival storage and access]] in [[Requirements|compliance]] with the  [http://en.wikipedia.org/wiki/Open_Archival_Information_System ISO-OAIS]  functional model and other [[wikipedia:Digital preservation|digital preservation]] standards and best practices. All of the Archivematica code and documentation is released under AGPL and Creative Commons open-source licenses.
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==Open Source OAIS==
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[[File:OAIS.png|thumb|left|500px|OAIS reference model]]
The Archivematica project is integrating a number of open-source tools to create a comprehensive digital archives system that is compliant with the [http://en.wikipedia.org/wiki/Open_Archival_Information_System ISO-OAIS] functional model and other [[wikipedia:Digital preservation|digital preservation]] standards and best practices. All of the Archivematica code and documentation is re-released under GPL and Creative Commons open-source licenses.
 
  
==Micro-Services design pattern==
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==Micro-services design pattern==
Archivematica implements a [[micro-services]] design pattern which is an alternative to digital preservation systems that are based on repository systems and J2EE frameworks. These are often too complex for small and medium-sized institutions to deploy and maintain. Instead of relying on a repository interface to a digital object store, the micro-services approach uses loosely-coupled tools to provide granular and orthogonal digital preservation services built around file-system storage. This reduces technical complexity for development and maintenance but is also noteworthy as a long-term preservation strategy because it provides archivists with direct, unmediated access to archival storage. Furthermore, file system technology is long-proven and extremely robust, typically outlasting the lifespan of enterprise information systems.
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Archivematica implements a [http://www.cdlib.org/services/uc3/curation/ micro-service] approach to digital preservation. The Archivematica micro-services are granular system tasks which operate on a conceptual entity that is equivalent to an OAIS information package: Submission Information Package (SIP), Archival Information Package (AIP), Dissemination Information Package (DIP). The physical structure of an information package will include files, checksums, logs, submission documentation, XML metadata, etc..  
  
==Virtualization technology==
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These information packages are processed using a series of micro-services. Micro-services are provided by a combination of Archivematica Python scripts and one or more of the free, open-source [[External tools|software tools]] bundled in the Archivematica system. Each micro-service results in a success or error state and the information package is processed accordingly by the next micro-service. There are a variety of mechanisms used to connect the various micro-services together into complex, custom workflows. Micro-services can be distributed to processing clusters for highly scalable configurations.
Using the latest in virtualization technology, each release of the Archivematica system packages a customized Xubuntu environment as a [http://en.wikipedia.org/wiki/Virtual_appliance virtual appliance], making it possible to run on top of any consumer-grade hardware and operating system, or even directly from a USB key. This means an entire [[Software|suite of digital preservation tools]] is now available to the average archivist from one simple installation. At the same time, the Archivematica architecture allows it to be componentized and installed directly on dedicated server hardware in a distributed, enterprise architecture to support large-scale, resource-intensive production environments.
 
  
==Receiving files for ingest==
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==Dashboard==
Archivematica can receive Submission Information Packages (SIP) in Bagit format and provides the ability to create SIP profiles using qualified Dublin Core and METS elements. However, the system will accept files for ingest with as much or as little metadata as is available. It runs the SIP through a series of ingest processes including unpacking, checksum verification and creation, unique identification, quarantine, format identification, format validation, metadata extraction and normalization. A variety of tools are used in each of these processes, including Easy Extract, Detox, UUID, CLAM AV, Thunar, Incron, Flock, JHOVE, DROID, NLNZ Metadata Extractor, File, FFident, File Information Tool Set (FITS), Xena, OpenOffice, Unoconv, FFmpeg, ImageMagick, and Inkscape. The web-based Archivematica Dashboard monitors the progress of each SIP, logs the results of each process, reports on any errors and prompts the archivist to trigger subsequent processes.
 
  
==Format specific preservation plans==
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[[Image:CreateSIPs-10.png|500px|thumb|left|In Dashboard: A transfer that is has completed micro-service jobs in the transfer workflow to be packaged into a SIP, arranged in Ingest or stored in the backlog]]
Archivematica maintains the original format of all ingested files to support migration and emulation strategies. However, the primary preservation strategy is to normalize files to preservation and access formats upon ingest. Archivematica groups file formats into [[Media_type_preservation_plans|media type preservation plan]]  (e.g. text, audio, video, raster image, vector image, etc.). Archivematica's preservation formats must all be open standards. Additionally, the choice of formats is based on community best practices, availability of free and open-source normalization tools, and an analysis of the significant characteristics for each media type. The choice of access formats is based largely on the ubiquity of web-based viewers for the file format.
 
  
The Archivematica media-type preservation plans will be moved to a structured, online [http://rdf.freebase.com/rdf/base.digitalformatpolicies format policy registry] that brings together format identification information with significant characteristic analysis, risk assessments and normalization tool information to arrive at default preservation format and access format policies for Archivematica. The goal is to make this registry interoperable with [http://www.nationalarchives.gov.uk/PRONOM/Default.aspx PRONOM], the upcoming [http://www.udfr.org/ UDFR] registry, the [http://testbed.planets-project.eu/testbed/public/about.faces Planets Testbed] and risk assessment methodologies like those being developed for the [http://p2-registry.ecs.soton.ac.uk/ Preserve2 registry]. Archivematica installations will use the registry to update their local, default policies and notify users if there has been a change in the risk status or migration options for these formats, allowing them to trigger a migration process using the available normalization tools. Users are free to determine their own preservation policies, whether based on alternate institutional policies or developed through the use of a formal preservation policy tool like Plato. The system is configured to make it easy to add new normalization tools and customize the media-type preservation plans.
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The web dashboard allow users to process, monitor and control the Archivematica workflow processes. It is developed using Python-based Django MVC framework. The Dashboard provides a multi-user interface that reports on the status of system events and makes it simpler to control and trigger specific micro-services. This interface allows users to easily add or edit metadata, coordinate AIP and DIP storage and provide preservation planning information. Notifications include error reports, monitoring of MCP tasks and manual approvals in the workflow. The dashboard also supports a transfer backlog linked to accession data as well as indexing, analysis, arrangement and minimal description of transfer(s) into SIP(s). An administration area allows users to manage storage locations, configuration of micro-services, alteration of preservation plans and user access levels.
  
==Preparing files for archival storage==
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==Format policies==
Archivematica packages Archival Information Packages (AIPs) using qualified Dublin Core, PREMIS and METS elements and Library of Congress’ Bagit format. Archivematica is able to interact with any number of storage systems using standard protocols (NFS, CIFS, HTTP, etc.) to allow for the flexible implementation of an archival storage and backup strategy. Archival storage options range from local hard disk, external hard disks, network attached storage devices, LOCKSS networks (e.g. MetaArchives, COPPUL), storage grids (e.g. iRODS, Bycast), cloud storage (e.g. Amazon S3, Microsoft Azure), etc..
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Archivematica maintains the original format of all ingested files to support migration and emulation strategies. However, the primary preservation strategy is to normalize files to preservation and access formats upon ingest. Archivematica groups file formats into [[Media_type_preservation_plans|format policies]]  (e.g. text, audio, video, raster image, vector image, etc.). Archivematica's preservation formats must all be open standards. Additionally, the choice of formats is based on community best practices, availability of free and open-source normalization tools, and an analysis of the significant characteristics for each media type. The choice of access formats is based largely on the ubiquity of web-based viewers for the file format.  
  
Archivematica creates Archival Information Packages (AIPs) using qualified Dublin Core, PREMIS and METS elements and Library of Congress’ Bagit format. Archivematica is able to interact with any number of storage systems using standard protocols (NFS, CIFS, HTTP, etc.) to allow for the flexible implementation of an archival storage and backup strategy. Standard operating system utilities can be used to provide backup functionality. Archival storage options range from local hard disk, external hard disks, network attached storage devices, LOCKSS networks (e.g. MetaArchive, COPPUL), storage grids (e.g. iRODS, Bycast), cloud storage (e.g. Amazon S3, Microsoft Azure), etc.. Where possible the archival storage directories are organized using a modified PairTree [http://confluence.ucop.edu/display/Curation/PairTree/] convention (e.g. local hard disk, NAS, etc.). Ideally, the storage platform provides its own fixity check functionality (e.g. Sun ZFS, LOCKSS, iRODS) but for those that do not, a fixity check daemon will be added to Archivematica.
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Archivematica format policies are managed in a structured, online format policy registry ([[Format_policy_registry_requirements|FPR]]) that brings together format identification information with significant characteristic analysis, risk assessments and normalization tool information to arrive at default preservation format and access format policies for Archivematica. This registry is synced with [http://www.nationalarchives.gov.uk/PRONOM/Default.aspx PRONOM], and the goal is to ultimately integrate other registries like the [http://corereg.arts.gla.ac.uk/PlanetsCoreRegistry/welcome.html Planets Core Registry] and/or the [http://www.udfr.org/ Universal Digital Format Registry] (UDFR). Archivematica installations use the FPR to update their local, default policies. Users are free to determine their own format preservation policies, whether based on alternate institutional policies or developed through the use of a formal preservation policy tool like Plato. The system is configured to make it simple to add new normalization tools and customize local format policies.
  
==Making files available for access==
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==From Transfer to SIP to AIP and DIP==
Archivematica prepares default Dissemination Information Packages (DIP) which are based on the designated access formats for each media type. Consumers can subsequently request AIP copies but caching access copies is a much more scalable approach that will address the majority of access requests in the most performant manner (i.e. reducing the bandwidth and time required to retrieve AIPs from archival storage and uploading them to the Consumer). The DIP access derivatives are sent via a REST interface to a web-based application such as ICA-AtoM or Archon for further enhancement of descriptive metadata (using ISAD(G), EAD, DACS, etc). These can then be arranged as accruals into existing archival descriptions to provide search and browse access to the institution’s analogue and digital holdings from one common web-based interface. The Archivematica Dashboard manages the read and write operations of the AIP to file storage and also coordinates the syncing of metadata updates between the AIPs and the access system.
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The primary function of Archivematica is to process digital transfers (accessioned digital objects), turn them into Submission Information Packages (SIPs), apply format policies and create high-quality, repository-independent Archival Information Packages (AIP) using [http://www.loc.gov/standards/mets/ METS], [http://www.loc.gov/standards/premis/ PREMIS] and [https://confluence.ucop.edu/download/attachments/16744580/BagItSpec.pdf?version=1 Bagit]. Archivematica is bundled with AtoM, but is designed to upload Dissemination Information Packages (DIP), containing descriptive metadata and web-ready access copies, to several access systems (e.g. Dspace, ContentDM, etc.).
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[[File:AMarch.png|500px|left|thumb|Archivematica Ingest infrastructure overview]]
  
 
==Lowering the barriers to best-practice digital preservation==
 
==Lowering the barriers to best-practice digital preservation==
The goal of the Archivematica project is to give archivists with limited technical and financial capacity the tools, methodology and confidence to begin preserving digital information today. The project has conducted a thorough [[OAIS Use Cases|OAIS use case]] and process analysis to synthesize the specific, [[UML Activity Diagrams|concrete steps]] that must be carried out to comply with the OAIS functional model from Ingest to Access. Wherever possible, these steps are assigned to software tools within the Archivematica system. If it is not possible to automate these steps in the current system iteration, they are incorporated and [[Documentation|documented]] into a manual procedure to be carried out by the end user. This ensures that the entire set of preservation requirements is being carried out, even in the very early iterations of the system. In short, the system is conceptualized as an integrated whole of technology, people and procedures, not just a set of software tools.
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The goal of the Archivematica project is to give archivists and librarians with limited technical and financial capacity the tools, methodology and confidence to begin preserving digital information today. The project has conducted a thorough [[OAIS Use Cases|OAIS use case]] and process analysis to synthesize the specific, [[UML Activity Diagrams|concrete steps]] that must be carried out to comply with the OAIS functional model from Ingest to Access. Through deployment experiences and user feedback, the project has expanded even beyond OAIS to address analysis and arrangement of transferred digital objects into SIPs and allow for archival appraisal at multiple decision points. Wherever possible, these requirements are assigned to software tools within the Archivematica system. If it is not possible to automate these steps in the current system iteration, they are incorporated and [[Documentation|documented]] into a manual procedure to be carried out by the end user. This ensures that the entire set of preservation requirements is being carried out, even in the early, pre 1.0 system releases. In short, the system is conceptualized as an integrated whole of technology, people and procedures, not just a set of software tools. For institutions that want technical assistance to install and customize Archivematica, optional [http://artefactual.com/archivematica.html technical support services] are provided by Artefactual Systems.
 
 
All of the software, documentation and development infrastructure are available free of charge and released under GPL and Creative Commons licenses to give users the freedom to study, adapt and re-distribute these resources as best suits them. Rather than spend precious funding on proprietary software licenses that restrict these freedoms, the Archivematica project encourages memory institutions tackling the challenges of digital preservation to pool their financial and technical resources in projects like Archivematica to maximize their long-term investments for the benefit of their colleagues, users and professional community as a whole.
 
  
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All of the software, documentation and development infrastructure are available free of charge and released under AGPL and Creative Commons licenses to give users the freedom to study, adapt and re-distribute these resources as best suits them. Rather than spend precious funding on proprietary software licenses that restrict these freedoms, the Archivematica project encourages memory institutions tackling the challenges of digital preservation to pool their financial and technical resources in projects like Archivematica to maximize their long-term investments for the benefit of their colleagues, users and professional community as a whole.
  
[[File:OAIS.png|thumb|left|300px|OAIS reference model]]
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[[Contribute code|Code contributions]], [https://projects.artefactual.com/projects/archivematica bug reports], wiki [[Special:UserLogin|documentation updates]] along with questions and feedback on the [http://groups.google.ca/group/archivematica discussion list] are strongly encouraged and welcomed.
  
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Commercial licenses and commercial use of the Archivematica name and logo [[trademark|trademarks]] may be negotiated with [http://artefactual.com Artefactual Systems] on a case-by-case basis.
  
[[File:Archivematica-architecture-7May2010-2.png|thumb|left|300px|Archivematica architecture - May 2010]]
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== Agile development ==
  
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Digital preservation systems must implement strategies that deal with technology obsolescence and incompatibility to ensure that digital objects remain authentic, accessible and useable for future use. The technologies that create digital objects and the technology available to manage them are constantly changing. Therefore, the Archivematica project has established an [[wikipedia:Agile software development|agile software development]] methodology to manage the perpetual maintenance and development of the system. This methodology is focused on rapid, iterative release cycles, each of which improves upon the system's [[Technical_Architecture|architecture]], [[requirements]], [[External_tools|tools]], [[documentation]], and [[development]] resources.
  
  
[[File:ArchivematicaDashboardScreencap05Mar2010.png|thumb|left|300px|Archivematica Dashboard - March 2010]]
 
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Latest revision as of 19:41, 9 March 2017

Main Page > Documentation > Technical Architecture > Overview

Open source OAIS[edit]

Archivematica provides an integrated suite of free and open-source tools that allows users to process digital objects from ingest to archival storage and access in compliance with the ISO-OAIS functional model and other digital preservation standards and best practices. All of the Archivematica code and documentation is released under AGPL and Creative Commons open-source licenses.

OAIS reference model

Micro-services design pattern[edit]

Archivematica implements a micro-service approach to digital preservation. The Archivematica micro-services are granular system tasks which operate on a conceptual entity that is equivalent to an OAIS information package: Submission Information Package (SIP), Archival Information Package (AIP), Dissemination Information Package (DIP). The physical structure of an information package will include files, checksums, logs, submission documentation, XML metadata, etc..

These information packages are processed using a series of micro-services. Micro-services are provided by a combination of Archivematica Python scripts and one or more of the free, open-source software tools bundled in the Archivematica system. Each micro-service results in a success or error state and the information package is processed accordingly by the next micro-service. There are a variety of mechanisms used to connect the various micro-services together into complex, custom workflows. Micro-services can be distributed to processing clusters for highly scalable configurations.

Dashboard[edit]

In Dashboard: A transfer that is has completed micro-service jobs in the transfer workflow to be packaged into a SIP, arranged in Ingest or stored in the backlog

The web dashboard allow users to process, monitor and control the Archivematica workflow processes. It is developed using Python-based Django MVC framework. The Dashboard provides a multi-user interface that reports on the status of system events and makes it simpler to control and trigger specific micro-services. This interface allows users to easily add or edit metadata, coordinate AIP and DIP storage and provide preservation planning information. Notifications include error reports, monitoring of MCP tasks and manual approvals in the workflow. The dashboard also supports a transfer backlog linked to accession data as well as indexing, analysis, arrangement and minimal description of transfer(s) into SIP(s). An administration area allows users to manage storage locations, configuration of micro-services, alteration of preservation plans and user access levels.

Format policies[edit]

Archivematica maintains the original format of all ingested files to support migration and emulation strategies. However, the primary preservation strategy is to normalize files to preservation and access formats upon ingest. Archivematica groups file formats into format policies (e.g. text, audio, video, raster image, vector image, etc.). Archivematica's preservation formats must all be open standards. Additionally, the choice of formats is based on community best practices, availability of free and open-source normalization tools, and an analysis of the significant characteristics for each media type. The choice of access formats is based largely on the ubiquity of web-based viewers for the file format.

Archivematica format policies are managed in a structured, online format policy registry (FPR) that brings together format identification information with significant characteristic analysis, risk assessments and normalization tool information to arrive at default preservation format and access format policies for Archivematica. This registry is synced with PRONOM, and the goal is to ultimately integrate other registries like the Planets Core Registry and/or the Universal Digital Format Registry (UDFR). Archivematica installations use the FPR to update their local, default policies. Users are free to determine their own format preservation policies, whether based on alternate institutional policies or developed through the use of a formal preservation policy tool like Plato. The system is configured to make it simple to add new normalization tools and customize local format policies.

From Transfer to SIP to AIP and DIP[edit]

The primary function of Archivematica is to process digital transfers (accessioned digital objects), turn them into Submission Information Packages (SIPs), apply format policies and create high-quality, repository-independent Archival Information Packages (AIP) using METS, PREMIS and Bagit. Archivematica is bundled with AtoM, but is designed to upload Dissemination Information Packages (DIP), containing descriptive metadata and web-ready access copies, to several access systems (e.g. Dspace, ContentDM, etc.).


Archivematica Ingest infrastructure overview

Lowering the barriers to best-practice digital preservation[edit]

The goal of the Archivematica project is to give archivists and librarians with limited technical and financial capacity the tools, methodology and confidence to begin preserving digital information today. The project has conducted a thorough OAIS use case and process analysis to synthesize the specific, concrete steps that must be carried out to comply with the OAIS functional model from Ingest to Access. Through deployment experiences and user feedback, the project has expanded even beyond OAIS to address analysis and arrangement of transferred digital objects into SIPs and allow for archival appraisal at multiple decision points. Wherever possible, these requirements are assigned to software tools within the Archivematica system. If it is not possible to automate these steps in the current system iteration, they are incorporated and documented into a manual procedure to be carried out by the end user. This ensures that the entire set of preservation requirements is being carried out, even in the early, pre 1.0 system releases. In short, the system is conceptualized as an integrated whole of technology, people and procedures, not just a set of software tools. For institutions that want technical assistance to install and customize Archivematica, optional technical support services are provided by Artefactual Systems.

All of the software, documentation and development infrastructure are available free of charge and released under AGPL and Creative Commons licenses to give users the freedom to study, adapt and re-distribute these resources as best suits them. Rather than spend precious funding on proprietary software licenses that restrict these freedoms, the Archivematica project encourages memory institutions tackling the challenges of digital preservation to pool their financial and technical resources in projects like Archivematica to maximize their long-term investments for the benefit of their colleagues, users and professional community as a whole.

Code contributions, bug reports, wiki documentation updates along with questions and feedback on the discussion list are strongly encouraged and welcomed.

Commercial licenses and commercial use of the Archivematica name and logo trademarks may be negotiated with Artefactual Systems on a case-by-case basis.

Agile development[edit]

Digital preservation systems must implement strategies that deal with technology obsolescence and incompatibility to ensure that digital objects remain authentic, accessible and useable for future use. The technologies that create digital objects and the technology available to manage them are constantly changing. Therefore, the Archivematica project has established an agile software development methodology to manage the perpetual maintenance and development of the system. This methodology is focused on rapid, iterative release cycles, each of which improves upon the system's architecture, requirements, tools, documentation, and development resources.